Direction finder loop and control



Aug. 1, 1933.

J.' A. PROCTOR DIRECTION FINDER LOOP AND CONTROL Filed May 22, 1928 3 Sheets-Sheet l Aug. 1, 1933.

J. A.'PROCTOR DIRECTION FINDER LOOP AND CONTROL Filed May 22, 1928 5 Sheets-Sheet 3 Patented Aug. 1, 1933 UEED STATES PATENT OFFICE DKRECTION FINDEE, LOOP AND CONTROL John A. Proctor, Lexington, Mass, assignor, by

mesne assignments, to General Electric Company, a Corporation of New York This invention relates to radio direction finding and more particularly to an improved rotatable loop structure and associated control mechar nisms. i-Ieretofore the loops used in radio direction finders were subject to serious disadvantages in that they were readily disarranged and rendered inoperative by the inclemency of the weather and the destructive action of salt water.

In addition, suitable mounting means adapted to maintain the loop structure in a stable, fixed position. permitting rotation of the loop proper in a pre-determined manner. have not been generally available. It is an object of the present invention to provide an improved loop structure for radio direction finders.

Yet another object of this invention is the provision of an improved mounting means for radio direction finders.

A further object of this invention is the provision of a novel method 0:" making such structures.

These and other desirable objects and advantages will be described in the folowing specification, and illustrated in the accompanying drawings, it being understood that the form shown is simply .a preferred embodiment of the invention, for since the underlying principles may be incorporated in ct. specific mechanical devices without departing from the spirit and scope of the present invention, it is not intended to be limited to the device shown, except as such limitations are clearly imposed by the appended. claims.

In the drawings, like numerals refer to similar parts thruout the several views, of which Fig. is a front elevation, partly in section, of the loop structure, its casing, pedestal, and

orting tripod;

Fig. 2 is a perspective View of an insulating washer;

bushing;

i is a vertical section of an insulating tube showing an improved method of weaving the loop leads thru the pedestal;

Fig. 5 is a vertical section of a portion of the main housing the region of the hand hole,

drive and collector rings.

Fig. 6 is a detail section on line 66 of Fig. 5 and shows the adjusting and positioning means of the drive mechanism;

Fig. '7 is a horizontal section on the line 7-7 is a perspective view of an insulating of Fig. 5, and shows the collector rings and brush assembly;

Fig. 8 is a front elevation of the brush assembly as viewed from the hand-hole in the main housing;

Fig. 9 is a side elevation partly in section of the main housing for the mechanical compen-sator and shows the indicator yoke and the leads from the collector rings together with the Sperry repeater support;

Fig. 19 is a plan view taken on line ill-10 of Fig. 9, looking down on the compass and the indicating mechanisms; and

Fig. 11 is a vertical section taken from line 11-41 of Fig. 9,. showing the indicator yoke, reading glass and Sperry repeater mechanism.

The loop structure, as shown particularly in Fig. 1, comprises a substantially rectangular frame composed of side tubular members 2' which may be of any suitable conducting material, such as aluminum. These tubular members are fitted into right-angled sockets 3, 4 and 5, forming an apex at two sides of the rectangle and at the bottom are fitted into the Y-connection 6. The angles 3, 4 and 5 are provided on either side with removable metallic plates 7, which provide access to the interior of the connections for a purpose to be described in detail later;

The loop proper consists of a plurality of turns'of suitable aerial wire woven thru suitable supports 8 and 9. A plurality of supports '8 is provided for the angular members 3, 4, 5, previously referred to, and are substantially rectangular' in shape and provided with a sufiicient number .of circumferentially arranged holes to accommodate the wires of the loop winding.

Referring to angle member l, it will be noted that the spacer member 8 is adapted to fit into a plurality of slots 10 and 11 at opposite corners of the angle proper. The cover plate 7, when removed, permits the introduction of member 8 into its appropriate slot, or in event of servicing, permits its ready withdrawal. The spaces in members 3 and. 5 are exactly similar to the one just described.

The combination spacer and terminal mounting member 9 is provided in the Y-member 6, the loop ends being designated respectively as 12 and 13 and the mid-point thereof as 14.

By the use of metal throughout a rigid construction is assured, together with ease of removing and mounting. To prevent complete shielding of the loop and therefore complete interception of electro-magnetic waves by the cas- 9 fitted into their respective slots.

having the necessary physical and dielectrical characteristics. By the interposition of these members between the metallic parts oftube 2 and angle 4, the electrical path around the loop casing is interrupted. The 'esultant Winding permits magnetic coupling with incoming sig nal'waves but eliminates any disturbing static coupling due to surrounding objects which would be the case if the loop casing formed the complete electrical circuit.

A preliminary step in the assembly of the loop 1 is the connectionof the various parts, the tubular members being fitted into the angles and secured thereto by any suitable means, the cover plates 7 being removed. The casing is then set on a suitable jig and the spacer members 3 and The loop winding 19, usually a continuous length of wire, is then threaded or woven thru the spacers, care being taken to maintain the proper spacial arverted U-shaped bearings.

rangement. The resultant winding is a cage-like structure of wires substantially parallel thruout their entire length. The ends of the loop, as above noted, are connected to suitable terminal posts 12 and 13, and the electrical mid-point of the loop is connected to a tab 14. This tab 14 is grounded to the casing at so thru a suitable condenser 21 which is usually of .5 mi capacity. This structure gives a symmetrical loop, the electrical characteristics of which will be referred to more in detail later.

The Y-casing 6 comprises the leg portion 22, having an inwardly shouldered portion 23, to which the mid-point lead of the loop is ground ed, and a recessed shoulder 24 into which is fitted the insulating plate 25' adapted to support the spacer member 9 and also thru which are threaded the loop leads 12 and 13.

Below portion 23 of the Y-member there is provided two integral concentric portions 25, 26, which in cross-section present substantially in- The outer member 25 is provided with a plurality of tabs 27to receive machine screws 28, which pass thru opening 29 in member 26 and engage openings 30 in the shaft 31.

The lower portion 26 above referred to is provided with a shouldered portion 32' which is fitted with bushings or bearing rings 33, substantially rectangular in cross section. This bearing member is secured to the ring in any suitable manner.

shanks 42 and tail-pieces 43. The head-pieces are shouldered as at 41' to fit in between members 39 and are provided with suitable apertures to receive the securing members 40. The shanks are fitted into members 41 in any suitable manner and are held therein by means of studs 44. The tail-pieces 43 engage suitable supports 45 which are aperture-d to receive suitable securing embers 46, which may be of any construction and are provided with base portions 47 adapted to fit the deck or cabin roof and are held in position thereon in any suitable manner, as by bolt and nut construction 48, and suitable washers 49. v

The construction just described provides a rigid yet adjustable supporting means the loop casing structure, and its pedestal, upon which said loop structure is adapted to be rotated.

The shaft 31, as above noted, is secured to the i -casing by the machine screws 23. At its lower portioirthis shaft is threaded at 50 in member 51 and secured thereto by set screws 52. Member 51 is see red to, rotatable casting 53 by any suitable means (not shown), the casting 53 being rotatably mounted on the base casting 54 secured to the deck by bolt and nut construction 55, suitable ball bearings being provided between mem-- here 53 and 54.

For permitting ease of assembly and disassembly, members 51 and 53 may have interposed a diaphragm member (not shown) secured by bolts 56 which permits rotation of the two members, and is adapted to take up any undue thus permitting increased flexibility in operation. Where such a diaphragm is used, suitable material is employed to prevent access of moisture to the interior of the structure.

The loop leads are carried thru the pedestal '1' in the following manner:--The leads are woven thru insulating members 57, made of cork, bakelite or other suitable insulating ma terial, and are thence woven thru insulating tubes provided with apertures 59 at the top and bottom sides.

Interiorly of the tubes 58 the leads are crossed over at a suijlicient angle to minimize capacity effects, such as would ordinarily be encountered between parallel disposed conductors. A plurality of these insulating devices and spacing members 57 is provided in order to prevent grounding contact of the loop leads with the metal of the conduit. By the use of a number of these members, reversal of production of the electrical fields around and about the wires is effected, such reversal being so calculated as to provide substantial neutralization of any capacity effects.

Subjacent to the member 54 and positioned within the cabin or deck house, is the main drive housing 60, secured to a supporting tubular member 61 by a plurality oi set screws 62. The member 61 is fixedly secured to the member 54 above referred to and acts a support for the drive housing. The drive housing is preferably cast as an integral member having'a circular abutting oprtion 63, the bottom out-turned apron or flange portion 64, and. an intermediate internal annular flange 65. There is also provided at one side of this upper portion 'a substantially rectangular portion comprised between lugs 66 and 67,

on to which is bolted the cover plate 68, the plate being secured to the legs by suitable machine screws 69, engaging tapped apertures '70, '71 in the lugs. The hand-hole thus provided permits the ready inspection of the loop driving mechanism, which will now be described in detail.

Hollow shaft 72, of any suitable conducting material, is secured at its upper portion to the member 53, and is substantially a-continuation of the member 31. suitable driving mechanism, comprising a collar 73 provided with spiral gear 74, engaging gear 75, the gears being out at an angle of 45 and the construction being substantially as shown and described in my combination case, Serial No. 29,919, filed March 13, 1925, for Rotating loop aerials. 1 V

The present device is distinguished from my prior construction by the inclusion of oiling members 76, 77, 78, bearing against the movable parts of the rotating mechanism and adapted to keep it fully lubricated. Oiling means 76 is positioned in a channel in the drive casing 79 and the oiling means 77 is channelled in the baseplate 80, which abuts the member 72, and is secured to member 79 by any suitable means, such as machine screws 81 engaging tapped apertures 82 in the casing 79. The details of the helical gearing and its associated controls have been described in the case above referred to, and such description is not repeated here except as'to the details necessary to point out the improvements over such prior structure.

Lubricating device 78 is provided in a ring 83 which is secured to flange of the drive housing, and this ring acts as a support for the ball bearings interposed between said lug and the lower portion of the driving shaft.

This lower portion of the driving shaft comprises the collar or tube 84, suitably apertured at 85 and 86 to receive machine screws 87 and 88, which are adapted to secure it to the tube 72. The tube 72 extends nearly to the bottom of the shouldered portion 89, being held therefrom by the screws above described. Member 84 is provided with a plurality of lugs 90, to which is secured the insulating plate 91 by means of a plurality of screws 92. Circumferentially of the insulating plate on top and bottom are placed a pair of opposed collector rings 93, 94, the rings being held in cooperative engagement with the insulating plate by means of machine screws 95, 96, these screws being insulated from opposite plates so that 95 forms an electrical contact or terminal for ring 93 and member 96 forms a like function for ring 94.

The leads from the collector rings are woven thru the insulating member 97 and pass thence upwardly to the members 58, being disposed, as above noted, to avoid capacity effects.

The bottom of member 84 forms an integral cup which is provided with a depending central extension 98. Plate 99 of the compensator described in my above application, fits over this extension and is secured to the shaft by any suitable means, such as machine screws 100. The shaft 101 of the compensator is provided with head plate 102, secured thereto by screws 103 and is associated with the loop drive which has been previously described in the application above referred to.

Referring now particularly to Figs. 7 and 8, there is shown a collector brush assembly comprising a base plate 104, upon which are positioned a pair of insulated mounting posts 105, secured to the base plate by suitable spring washers 106 and nuts 107. At the upper portion of these supporting posts, there is superimposed a spaced insulating plate 108. This plate is tapped This shaft 72 is provided with tures 112' adapted to receive studs 113. These studs are fixed to the bottom of the casing by any suitable means, being threaded on either bottom portions and fixedly secured thereto by the combination locking nuts and washers 11 1.

The collector brushes 116, 117 are secured to the mounting posts in any suitable fashion, as by means of a plurality of screws 115. These collector brushes comprise a plurality of strips of conducting metal, such as copper, shown more particularly in Fig. 7, the strips being so arranged as to provide maximum constant pressure on the members bearing against collector rings 93, 94. Suitable terminals 118, 119 are connected to the brushes thru the intermediacy of connecting strips 120, 121. Flexible leads 122, 123 are fastened to the terminals in any approved manner, and lead to the radio apparatus positioned in the base receiver of the direction finder.

The casing 63 is provided with an opening to permit the introduction and removal of this brush assembly with a minimum of trouble. An aperture is provided with a cover 124: adapted to be secured to the casing in any suitable manner, as by means of screws 125, a weather-proof gasket such as valenoid or the like 126 being interposed between the cover and the casing. The casing is also provided at either side of the aperture referred to above with inwardly projecting shelf portions 127, upon which are mounted the studs 113 above referred to.

When it is desired to remove the brush assembly for any purpose, whatsoever, it is merely necessary to remove the cover, unscrew the locking member 109, and disconnect the terminal leads 122, 123, after which the base 10% is lifted up and out of engagement with the supporting studs 113, whereupon the entire structure may be withdrawn from its position. It will now be appreciated that such a construction enables the assemblage and mechanical and electrical testing of the brush assembly as a separate unit before it is placed in its appropriate position in the direction finder assembly, and further that this case of assembly likewise affords a like degree of disassembly. The collector brush assembly has but three points of contact with the fixed casing, and by this simplicity of structure and ease of servicing facilitates the manufacture and maintenance of the direction finder assemblies.

If it is necessary to raise the brush unit in order to insure perfect contact with the respective collector rings, it is merely necessary to insert washers of appropriate thickness between base plate 104 and the locking nuts 114.

In Fig. 9 there is shown the main housing for the compensator 128, which is secured to the main drive casing by suitable means, such as screws 129, the mechanical part of which is substantially shown and described in my above designated application, Serial No. 29,919.

The shaft 101 is prolonged thru the bushing 130 of the compensator housing and is adapted at its lower end 131 to receive the tapped central boss 132 of the indicating yoke 133. This yoke is secured to shaft 101 by means of set screw rnits the reading of 12 .Theyoke is substantially U-shaped in cross section, comprisingtwo lateral arms 133, 133', depending from the central supporting boss sec-- tions 132. At either end of the arms, the yoke members are provided with slotted portions 135, 136, adapted to receive members 137, l38, which are secured to the yoke'by suitable screws 139. Members 137, 138 are prolonged forwardly to provide clamping support means for therotating glass 140. Thisglass is provided with a suitable frame 141, coacting with thereceiver portion 142 into which the lens is adapted to fit. Suitable screws 1 13 are provided to secure the two parts of the, lens holder in cooperative engagement;

Member 142 is adapted for rotation about spindles 1 14. at right angles to members 137, 138. Stop members, such as screws 145, 146, are secured to members 137, 138 immediately behind spindles 14 i, and are adapted to serve as limiting stops for the lens structure. The lens supporting armsl37, 138 are possessed of several springs and are suitably conformed to provide frictional engagement with the lens support in order that it may be variably adjusted and held in any desired position.

The lens supporting construction shown perthe scale at any position, by merely reversing the lens, thereby obviating the necessity of the operator shifting his position and along its middle axis is provided with a plurality of lines. These lines comprise a top line which is normally filled with a black pigment, and a bottom line in the same vertical plane as the black line, the'bottom line being filled with a red pigment for the purpose of differentiating it from the upper line. The function of these lines will be described in detail hereinafter;

The direction plate is secured to the yoke inember in the following manner. The supporting member 148 is secured to the'yoke by means of suitable screws 149. interposed between member 148 and 147 are suitable connection means 150, which may be a gasket of felt or any other suitable material. member there is provided a securing lrnob 151, which is adapted to receive the screw member 152. This screw passes thru a suitable aperture in the geometric center of the sighting plate and engages the bottom supporting plate 153, which is spaced from the sighting plate by suitable gasket material as above described. By the means just described, the sighting plate is secured to the yoke member and adapted to rotated therewith.

In sighting, the operator sights along the black line, taking care that he does'not observe any portion of the red line. A showing of any por tion of the red line would immediately indicate error in the reading, due to dii'raction or parallax. These red and black lines are distinguished from the red and white sense pointers 154i, 155, which are integralwith the yoke structure and indicate the direction of the incoming signal. These sense indicators are at right angles "to the above lines, and are distinguished therefrom by the-functions above noted.

Centrally of this supporting Asshown in Fig. 11, the indicating structure just described is fitted for the receiver casing, and is adapted to co operate with the dummy compass or a Sperry'repeater, indicated gen erally by 156.: f

Inoperation, the navigate: or radio operator, rotates the loop by means of the hand wheel until a desired maximum signal is received in the radio set associated with the loop. The loop is then rotated until a null point is reached. The null point is used to check up the point or direction of maximum signal reception, due to its relative clearness from interfering signals and other trouble. As is well known, the null point is substantially 96" from the point of maximum signal reception, and serves to determine the aforesaid point with greater definiteness than is possible by trying to measure the strength of signal either side of the maximum.

The point of maximum signal reception and the .null point are read, oil on the scale, the lens being rotated, if necessary, to permit ease of reading.

The direction or" the signal having been establlshed and noted with respect to the scale set-- ting oi the instrument, the corrected reading is transmitted to the navigator to enable him. to determinephis position and co rse, as may be necessary.

It will now be seen that there has been provided a novel loop structure and loop rotating sechanism, together with a loop indicating de vice, the whole being adapted to permit the speedy reception of signals whil compensating for the electrical and magnetic disturbances set up as a result of the proximity of ships rigging, hold, electrical machinery, etc., while assuring proper reading of the instrument with a mini-- mired chance of error due to parallax.

Having the several turns of the loop symmetrically arranged within its shield preserves the symmetry of, electrical capacity to ground, when the loop is tuned and nearer metallic objects. i

I claim: I

1. In a radio direction finder, the combination with the loop aerial comprising a plurality of concentric turns, of a substantially tubular metallic casing having a plurality of straight sides and itself concentric with and enclosing said loopturns from the Weather of the external atmosphere; apertured spacing plates extending inside the metallic enclosing tube across it hollow interior at its corners at substantially forty-five degrees to its sides, said tube supporting said plates, and said loop-wires threading thru the apertures in the spacing plates; said metallic enclosing tube being formed at its corners with apertures extending in both directions from said corners along the sides of the tube and providing access to both sides of said spacing plates; metallic platescovering said tube-apertures and removably secured'to the metallic walls of the tube around said apertures; an insulating member thru which said plural loop turns extend, said 11161111361 being interposed between neighboring thru said hollow shaft; said mechanical connection between the hollow shaft and enclosing tube sustaining the weight of the entire loop structure above it including the metallic enclosing tube itself and the spacing plates and loop-turns, and causing rotation or" said structure as the unitary rotatable element of the direction finder.

2. In a radio direction finder, the combination with the loop aerial comprising a plurality of concentric turns, of a tubular metallic casing concentric withand enclosing said loop-turns from the weather of the external atmosphere; means inside said metallic enclosing tube and supporting the loop-turns in insulated relations with the tube; an insulating tube spacing apart two neighboring ends of the metallic enclosing tube and having its hollow interior alined with the hollow interior of said metallic tube, said loop-turns extending thru said insulating tube and the latter forming an electrical opening in the circuit of the concentric enclosing metallic tube but enclosing the interior of the metallic tube and the enclosed loop turns from the weather; means holding said metallic and insulating tubes in said cooperative relations; said enclosing tube including at its bottom a separate hollow open-ended metallic Y-inember of which two hollow legs space apart two other neighboring ends of the enclosing tube and communicate with the interior of the insulating tube and the rest of the metallic tube, the wires of the plural loop leads extending thru said two hollow legs of the Y-member; the plural leads from the loop extending out of the metallic enclosing tube by way of the open end of said third hollow leg of the Y-member; and a hollow rotatable shaft vertically disposed and supporting said third hollow leg of the Y-member and mechanically connected thereto for rotation thereof, said third hollow leg itself supporting the entire loop-structure above it as a unitary rotatable element of the direction finder including the metallic and insulating tubes and the enclosed loop-turns, said loop leads extending down thru said hollow shaft.

3. In a radio direction finder the combination with the loop aerial comprising a plurality of concentric turns, of a tubular metallic casingconcentric with and enclosing said loop-turns from the weather of the external atmosphere and having at its bottom a hollowdownwardly projecting metallic member communicating in both lateral directions with the interior of the rest of the tubular enclosing structure, and forming with the adjacent ends of the tubular structure a Y-shaped metallic construction; two facing alined ends of the tubular structure at a location other than said downwardly projecting member being substantially spaced apart to provide an open circuit structure; a tube of insulating material having its interior alined with the facing interiors of said spaced ends and closing the space against the weather; means holding the metallic and insulating tubes in said cooperative relation; means inside the metallic enclosing tube and insulating the loop-turns therefrom and hollow metallic shaft secured to and alined with said downwardly projecting portion for rotation of the entire tubular structure as a unit of the direction-finder.

i. In a radio direction finder, the combination with a loop aerial comprising a plurality of concentric turns, of a tubular metallic casing concentric with and enclosing said loop-turns from the weather of the external atmosphere; and means supporting the loop-turns in insulated relations with said metallic enclosing tube; the

bottom of the hollow metallic enclosing tube including a hollow open-ended downwardly projecting metallic portion thru which extend the leads of said loop aerial; the metallic enclosing tube having two neighboring spaced but facing ends at a location other than said hollow openended metallic projecting portion; an insulating member apertured for passage or" said loopturns and holding neighboring ends of the metallic enclosing tube in spaced-apart insulated relations to one another, said insulating member enclosing the space between the ends of the metallic enclosing tube and cooperating with it in enclosing the plural loop-turns from the weather; and a hollow metallic rotatable shaft supporting said hollow metallic projecting portion, alined therewithv for downward passage of the loop-lcads, and mechanically connected with said metallic projecting portion for rotation of the metallic enclosing tube, said metallic projecting portion supporting the entire loopstructure above it as a unitary rotatable element of the direction finder including the metallic enclosing tube and the apertured insulating member.

5. In a radio direction finder, the combination with the loop aerial comprising a plurality of concentric turns, of a tubular metallic casing concentric with and enclosing said loop-turns from the weather of the external atmosphere; means inside said metallic enclosing tube and insulating the loop-turns from said tube; the bottom of the casing being provided with a hollow openended metallic Y-member of which two hollow legs are mechanically connected with two neighboring ends of the tubular metallic casing alined with said two legs of the Y-member, the loop-leads extending thru said two legs and out of the loop-turn enclosing structure by way of the open-ended third leg of the Y-member; the metallic enclosing tube having two neighboring alined and facing but spaced-apart ends at a portion exposed from said metallic Y-member; and an insulating member apertured for passage of said loop-turns and holding said neighboring ends of the metallic tube in their said spacedapart relation and in insulated relations to one another, said insulating member enclosing the.

space between the spaced-apart ends of the metallic tubes and cooperating with the latter in enclosing the plural loop -turns from the weather; and a hollow rotatable shaft vertically disposed and supporting said third hollow leg of the Y-member and mechanically connected thereto for rotation thereof, said third hollow leg itself supporting the entire loop-structure above it as a unitary rotatable element of the direction finder including the metallic tube and apertured insulating member and the enclosed loop-turns, said loop leads extending down thru said hollow shaft.

6. In a radio direction finder, the combination with the loop aerial comprising a plurality of concentric turns, of a tubular metallic casing concentric with and enclosing said loop-turns from the weather of the external atmosphere, and having at its bottom a hollow downwardly projecting metallic member communicating in both lateral directions with the interior of the rest of the tubular enclosing structure and forming with the adjacent ends of the tubular structure a Y-shaped metallic construction; a spacing and insulating member interposed between neighboring alined ends of the tubular metallic structure at a location other than said downwardly pro jecting member at which location the insulating member open circuits the electrical circuit of the tubular enclosing structure, said insulating memher being apertured for the passage of the loopwires but closing the space between said neighboring ends of the metallic tubular structure and cooperating with the latter in enclosing the loopturns from the weather; means insulating the metallic enclosing tube from the loop-turns; and

tially symmetrical and intersecting, relationship.

8. In a radiov direction finder, a loop, leads from the loop, and means to mount the leads in substantially fixed relationto the loop, said means including insulating tubes apertured at both ends to provide lead-in apertures for the leads, and said leads passing through said tubes diagonally of the apertures and of each other.

9. In a radio direction finder, a loop, leads from the inid-point and ends of the loop, a tubular pedestal, a condenser mounted on the pedestal and connected to the mid-point lead, a separate tubular member of insulating material Within the pedestal, said tubular member having lateral opposed apertures at its ends, said loop end leads passing through one pair of said opposed apertures and reversely through said other pair of opposed apertures, thus forming means for suspending said tubular member.

JOHN A. PROCTOR, 

